1 Kolleru is freshwater between delta regions; 2 Pulicat is a brackish lagoon near the Tamil Nadu boundary.

Districts: APSDMA. Rivers: APSAC WMS. Educational site locators: OpenStreetMap and official project records.

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Kolleru occupies the inter-delta lowland; Pulicat lies far to the south behind a coastal barrier. Label the first as a freshwater lake and the second as a brackish lagoon. Their relative positions and formation answer different types of question.